Function exception

example/cacheHierarchy/fkYAML/node.hpp:1653–1657

@brief Construct a new exception object with an error message. @param[in] msg An error message. @sa https://fktn-k.github.io/fkYAML/api/exception/constructor/

    /// @param[in] msg An error message.
    /// @sa https://fktn-k.github.io/fkYAML/api/exception/constructor/
    explicit exception(const char* msg) noexcept {
        if (msg) {
            m_error_msg = msg;
        }
    }

public:
    /// @brief Returns an error message internally held. If nothing, a non-null, empty string will be returned.